Purpose of Program for Monitoring Hanoi Drinking Water
Community Service Project
- Provide information to the local and international community in Hanoi on drinking water safety.
- Determine Arsenic levels in Hanoi water supply
- Other parameters tested: nitrate, manganese, iron, hardness, total coliform, fecal coliform and free chlorine.
- Sampling sites: Households in the city nearby 13 main water supply treatment plants (WSPs) and 4 smaller water treatment stations
Sampling Period
- 27 rounds from May 2009 to Apr 2016, sampled quarterly
Water Supply Plants in Hanoi
Water Supply Plants
Field Program
- 32-35 water samples taken on each round
- Sample location description
- GPS location
- Field parameters tested
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- Free chlorine
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- Turbidity
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- pH
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- Temperature
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Sample Handling
- Sample Collection
- 250 ml PE bottles are filled with water samples and stored and cooled by ice in a sealed container
- Samples delivered to the analytical laboratory within 8 hours
- Sample Acidification
- Samples for metallic parameters analysis are acidified with 3ml HNO3 solution
Laboratory Analysis
- Laboratory for Arsenic, other metals, and nitrate analysis:
- From May 2009 to December 2010: Institute Of Geological Sciences. Add: 84 Chua Lang Street, Dong Da, Hanoi.
- From December 2010 to Present: Department of Environmental Quality Analysis (DEQA) of Institute of Environmental Technology (IET) – Vietnam Academy of Science and Technology (VAST). Arsenic concentrations were measured by Inductively Coupled Plasma – Mass Spectrometry (ICP-MS)
Testing Quality Assurance
- Chain of Custody:
- At the Institute a “Chain of Custody/Analytical Request Form” is filled in and signed by both the DS-Intl staff and the Lab staff
- Duplicates:
- Each round: duplicate samples account for 10% of total samples
- Blanks:
- One distilled water and three bottled water brands samples tested
- Matrix spikes for coliforms:
- Samples taken from the West Lake
Water Quality Standards
Primary Water Quality Standards (for drinking water)
Sampling Locations
- Sampling site selection criteria follows procedures:
- Tap water at households using treated water
- The closest residential place from the targeted water plant (normally not further than 1km)
- A few additional locations were selected to provide a broader coverage in the city
- Samples from the chosen locations were consistently sampled each quarter over the study period
Arsenic Results
Arsenic
- Odorless and tasteless.
- Enters drinking water supplies from agricultural and industrial practices or natural deposits in the earth
- Arsenic has been linked to cancer of the bladder, lungs, skin, kidney, nasal passages, liver, and prostate (EPA, USA)
- National technical regulation on drinking water quality (QCVN 01:2009/BYT) and WHO standards allow maximum contaminant level (MCL) of 10 ppb for Arsenic
Results
- During Seven years of the study, 15 sampling sites (43% of 35 total sites) have been found to have average arsenic levels over the MCL of 10 ppb (µg/L)
- Overall, average arsenic levels at these 15 sampling sites was 19.63 ppb
- Of those 15 locations, the site with the lowest average arsenic level was 12.50 ppb, and the site with the highest was 28.24 ppb